Understanding the Role of the Chemical Composition of Aggregates on the Moisture Susceptibility of Asphalt Mixtures

Rock mineralogy, which is determined by the rock chemical composition, is a fundamental factor in determining the quality of adhesion and moisture susceptibility of asphalt-aggregate systems in hot mix asphalt (HMA) materials. This work aims to identify the chemical compositional properties of aggregates that have a direct influence over the adhesive quality of these systems. To accomplish this goal, three different lithologies with an ample mineralogical and chemical spectrum (i.e. quartzite, granodiorite and serpentinite) were tested. The testing specimens consist of cylindrical 1-inch rock cores bonded to a metallic stub with a 20 µm thick Pen 60-70 (1/10 mm) asphalt film. A new pull-off debonding set-up experiment was developed to test the specimen under a tensile displacement-controlled condition of 10 mm/min. Specimens were tested in dry condition, and after 1, 7 and 15 days of being submerged in type 1 water (i.e. ultrapure water that has been depleted of most contaminants). The main findings of this work are: i) water deteriorates the bonding quality of the asphalt-aggregate systems, as expected; ii) rocks of mafic composition (i.e. high magnesium and iron contents; e.g. serpentinite) have better resistance to moisture damage than felsic rocks (i.e. high quartz and feldspar contents; e.g. quartzite and granodiorite); iii) Al₂O₃, Fe₂O₃, MnO, MgO, SO₃, Cr₂O₃ and NiO oxides show to contribute to moisture damage resistance, whereas the only oxide that was seen to promote moisture susceptibility was SiO₂; and iv) results suggest that there might exist an aggregate-asphalt reaction altering the mechanical properties at the interface of these systems.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AFK40 Standing Committee on Surface Requirements of Asphalt Mixtures.
• Corporate Authors:

  Transportation Research Board

  ,    
• Authors:
  • Cala, Andr�s
  • Caro, Silvia
  • Lleras-Jacobsen, María
  • Rojas-Agramonte, Yamirka
• Conference:
  • Transportation Research Board 98th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2019-1-13 to 2019-1-17
• Date: 2019

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 7p

Subject/Index Terms

• TRT Terms: Aggregates; Asphalt mixtures; Chemical composition; Moisture content
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 01697373
• Record Type: Publication
• Report/Paper Numbers: 19-04533
• Files: TRIS, TRB, ATRI
• Created Date: Mar 1 2019 3:50PM